Btrfs: fix assert screwup for the pending move stuff

Wang noticed that he was failing btrfs/030 even though me and Filipe couldn't
reproduce.  Turns out this is because Wang didn't have CONFIG_BTRFS_ASSERT set,
which meant that a key part of Filipe's original patch was not being built in.
This appears to be a mess up with merging Filipe's patch as it does not exist in
his original patch.  Fix this by changing how we make sure del_waiting_dir_move
asserts that it did not error and take the function out of the ifdef check.
This makes btrfs/030 pass with the assert on or off.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/send.c

@@ -2774,8 +2774,6 @@ static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino)
 	return 0;
 }
 
-#ifdef CONFIG_BTRFS_ASSERT
-
 static int del_waiting_dir_move(struct send_ctx *sctx, u64 ino)
 {
 	struct rb_node *n = sctx->waiting_dir_moves.rb_node;
@@ -2796,8 +2794,6 @@ static int del_waiting_dir_move(struct send_ctx *sctx, u64 ino)
 	return -ENOENT;
 }
 
-#endif
-
 static int add_pending_dir_move(struct send_ctx *sctx, u64 parent_ino)
 {
 	struct rb_node **p = &sctx->pending_dir_moves.rb_node;
@@ -2902,7 +2898,9 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
 	}
 
 	sctx->send_progress = sctx->cur_ino + 1;
-	ASSERT(del_waiting_dir_move(sctx, pm->ino) == 0);
+	ret = del_waiting_dir_move(sctx, pm->ino);
+	ASSERT(ret == 0);
+
 	ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
 	if (ret < 0)
 		goto out;